Pilocarpine and epinephrine are indicated for the management of ocular pressure. Pilocarpine, or (3S-cis)-ethyldihydro-4-[(1-methyl-1H-imidazol-5yl)methyl]-2(3H)-furanone, is a parasympathomimetic drug that lowers intraocular pressure by increasing facility of outflow of aqueous humor from the eye. Epinephrine, or 4-[1-hydroxy-2-(methyl-amino)ethyl]-1,2-benzenediol, is a sympathomimetic drug that diminishes intraocular pressure by the dual effects of reducing aqueous secretion and increasing facility of outflow. These two drugs are commonly used in separate solutions for controlling glaucoma, and sometimes they are used in combination in solution for the same therapeutic purpose. See Handbook of Ocular Therapeutics and Pharmacology, by Ellis and Smith, 3rd Edition, pages 171, 172, 192 and 193, published 1969 by C. V. Mosby Company, St. Louis, Mo.; and Physicians' Desk Reference for Ophthalmology, page 85, 1976/1977 Edition, published by Medical Economics Company, Oradell, N.J.
In either dosage solutions, serious shortcomings are frequently associated with the use of the solutions. For example, solutions require periodic applications at intervals throughout the day and night, and this results in the eye receiving a massive and unpredictable amount of drug(s) at each application. This kind of application results in the level of drugs(s) surging to a peak, followed by a decline in the concentration of the drug(s). Often, the applied drug(s) are washed away by tear fluid leaving the eye without medication(s). Other shortcomings associated with the pulse-dosage patterns of ocular solution therapy are blurred vision attributed to loss of accommodation, possible disruption of the barrier and transport properties of the corneal epithelium, and epithelial damage arising from the presence of acid buffers and/or eyedrop preservatives in the solution(s), as reported in Invest. Ophthalmol. Visual. Sci., Volume 16, No. 10, pages 899 to 911, 1977. Such eyedrop formulation components are not required for the functioning of the described invention.
In the light of the above presentation, it is immediately evident a long-felt need exists for an ocular system for dispensing pilocarpine and epinephrine to the eye substantially free of the tribulations associated with the prior art dosage forms. The critical need exists for a system that can dispense both pilocarpine and epinehprine in therapeutically effective amounts from the same system for the intended benefits of the drug(s). Particularly, the want persists for a system that can house the two structurally and biologically active different drugs without any interaction, and with the drugs in the system combined and available for immediate and future in vivo use at therapeutically effective rates. It will be appreciated by those versed in the medical and dispensing arts, that if the system is provided that can dispense simultaneously pilocarpine and epinephrine for the management of intraocular pressure, such a system would have a definite use and represents a substantial contribution to the arts. Likewise, it will be further appreciated by those versed in the arts, that if an ocular therapeutic system is made available for delivery of these drugs simultaneously for the management of glaucoma, such a system would have a positive value and represent an unexpected advancement in the field of ocular pharmacology.